1. Field of the Invention
This invention relates to belt-type power transmissions for vehicles of various types, and more particularly to a variable width driving pulley for a continuously variable transmission that uses a belt for transmitting power from an engine to a drive wheel of a vehicle.
2. Description of the Related Art
Continuously variable power transmissions utilizing a V-belt and pulley drive system for transferring power from a driving pulley to a driven pulley are well known. In such systems a driving pulley, connected with the output shaft of an engine, and a driven pulley, connected with the drive wheel of a vehicle, are each made to include a fixed pulley wall and a movable pulley wall, with the spacing between the respective pulley walls determining the drive ratio from the engine to the drive wheel. An example of such a transmission system is shown and described in U.S. Pat. No. 4,493,221, which issued Jan. 15, 1985, to Richard F. Stieg et al.
Generally, such transmissions are used as a part of the drive system of such devices as snowmobiles, automobiles, golf cars, utility vehicles, and the like. When in use in such vehicles, it is desirable that the transmission provide rapid response to a demand for acceleration, both upon initial startup from a rest position, as well as while the vehicle is moving and a demand arises for additional torque to increase or to maintain the speed of the vehicle as, for example, during a climb up a hill or other inclined surface. Heretofore, such belt-type, continuously variable transmissions have been characterized by relatively slow response to such increased torque requirements, and it is therefore an object of the present invention to provide a driving pulley for a continuously variable transmission in which the response to increased torque requirements at normal and high operating speeds is more rapid than in conventional devices of that type.
Another object of the present invention is to provide a driving pulley for a continuously variable transmission wherein the pulley provides increased responsiveness both at initial take-off of the vehicle, as well as at higher, cruise speed conditions.